Staircase for a toy building set



FIG. 1 is a top perspective view of a staircase for a toy building setshowing my new design;

FIG. 2 is a bottom perspective view thereof;

FIG. 3 is a rear elevational view thereof;

FIG. 4 is a left side elevational view thereof;

FIG. 5 is a front elevational view thereof;

FIG. 6 is a right side elevational view thereof;

FIG. 7 is a top plan view thereof; and,

FIG. 8 is a bottom plan view thereof.

The ornamental design for a staircase for a toy building set, as shownand described.